RESUMEN
Engineered nanomaterials (ENMs) are released into the environment with unknown implications in the food chain. Recent findings demonstrate that ENMs may accumulate and/or increase concentrations of the component metal or carbon nanomaterials in the fruits/grains of agricultural crops, have detrimental or beneficial effects on the agronomic traits, yield, and productivity of plants, induce modifications in the nutritional value of food crops, and transfer within trophic levels. Given this information, important questions needed to be resolved include a determination of actual or predicted concentrations of ENMs through the development of new and perhaps hybridized analytical tools, assessment of the nutritional content modifications and/or accumulation of ENMs, component metal, and cocontaminants in edible plants and their implications on human diet, nutrition, and health, assessment of the consequences of ENM-induced changes in soil health, physiological process, and yield on agricultural production and food security, and transfer of ENMs in trophic levels. Given the significant implications of ENMs exposure and the rather large knowledge gaps that exist, it will be prudent to observe judicious and targeted use of ENMs so as to minimize environmental release until a comprehensive environmental fate and effects assessment can be undertaken.
Asunto(s)
Frutas/química , Nanoestructuras/análisis , Plantas Comestibles/química , Contaminantes del Suelo/análisis , Biotransformación , Monitoreo del Ambiente , Cadena Alimentaria , Frutas/crecimiento & desarrollo , Humanos , Estado Nutricional , Valor Nutritivo , Plantas Comestibles/crecimiento & desarrollo , Contaminantes del Suelo/metabolismoRESUMEN
Currently, most of the nanotoxicity studies in plants involve exposure to the nanoparticles (NPs) through the roots. However, plants interact with atmospheric NPs through the leaves, and our knowledge on their response to this contact is limited. In this study, hydroponically grown cucumber (Cucumis sativus) plants were aerially treated either with nano ceria powder (nCeO2) at 0.98 and 2.94 g/m(3) or suspensions at 20, 40, 80, 160, and 320 mg/L. Fifteen days after treatment, plants were analyzed for Ce uptake by using ICP-OES and TEM. In addition, the activity of three stress enzymes was measured. The ICP-OES results showed Ce in all tissues of the CeO2 NP treated plants, suggesting uptake through the leaves and translocation to the other plant parts. The TEM results showed the presence of Ce in roots, which corroborates the ICP-OES results. The biochemical assays showed that catalase activity increased in roots and ascorbate peroxidase activity decreased in leaves. Our findings show that atmospheric NPs can be taken up and distributed within plant tissues, which could represent a threat for environmental and human health.
Asunto(s)
Cerio/metabolismo , Nanopartículas/química , Hojas de la Planta/fisiología , Antioxidantes/metabolismo , Transporte Biológico , Cucumis sativus/enzimología , Cucumis sativus/ultraestructura , Pruebas de Enzimas , Hidroponía , Nanopartículas/ultraestructura , Hojas de la Planta/enzimología , Hojas de la Planta/ultraestructura , Polvos , Factores de TiempoRESUMEN
Manufactured nanomaterials (MNMs) are increasingly produced and used in consumer goods, yet our knowledge regarding their environmental risks is limited. Environmental risks are assessed by characterizing exposure levels and biological receptor effects. As MNMs have rarely been quantified in environmental samples, our understanding of exposure level is limited. Absent direct measurements, environmental MNM concentrations are estimated from exposure modeling. Hazard, the potential for effects on biological receptors, is measured in the laboratory using a range of administered MNM concentrations. Yet concerns have been raised regarding the "relevancy" of hazard assessments, particularly when the administered MNM concentrations exceed those predicted to occur in the environment. What MNM concentrations are administered in hazard assessments and which are "environmentally relevant"? This review regards MNM concentrations in hazard assessments, from over 600 peer-reviewed articles published between 2008 and 2013. Some administered MNM concentrations overlap with, but many diverge from, predicted environmental concentrations. Other uncertainties influence the environmental relevance of current hazard assessments and exposure models, including test conditions, bioavailable concentrations, mode of action, MNM production volumes, and model validation. Therefore, it may be premature for MNM risk research to sanction information on the basis of concentration "environmental relevance".
Asunto(s)
Exposición a Riesgos Ambientales/análisis , Sustancias Peligrosas/análisis , Modelos Teóricos , Nanoestructuras/análisis , Medición de RiesgoRESUMEN
In this study, Brassica chinensis L seedlings after 6 weeks of soil cultivation were treated with foliar application of TiO2 NPs (20 mg/L) for different times. Transcriptomics analysis was employed to investigate the impact of TiO2 NPs on the physiology, growth, and yield of B. chinensis L. Results showed that TiO2 NPs' exposure significantly increased the biomass, total phosphorus, and catalase enzyme activity by 23.60, 23.72, and 44.01%, respectively, compared to the untreated ones (not bulk or ion).TiO2 NPs increased the leaf chlorophyll content by 4.9% and photosynthetic rate by 16.62%, which was attributed to the upregulated expression of seven genes (PetH, PetF, PsaF, PsbA, PsbB, PsbD, and Lhcb) associated with electron transport in photosystem I and light-harvesting in leaves. The water balance of B. chinensis was improved correlating with the altered expressions of 19 aquaporin genes (e.g., PIP2;1 and NIP6;1). The expressions of 58 genes related to plant hormone signaling and growth were dysregulated, with notable downregulations in GA20, SnRK2, and PP2C and upregulations of DELLAs, SAM, and ETR. Moreover, the 11 tricarboxylic acid cycle genes and 13 glycolysis genes appear to stimulate pathways involved in promoting the growth and physiology of B. chinensis. This research contributes valuable insights into new strategies for increasing the yield of B. chinensis.
Asunto(s)
Brassica , Regulación de la Expresión Génica de las Plantas , Fotosíntesis , Hojas de la Planta , Proteínas de Plantas , Titanio , Transcriptoma , Titanio/química , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/química , Brassica/genética , Brassica/metabolismo , Brassica/crecimiento & desarrollo , Brassica/efectos de los fármacos , Brassica/química , Fotosíntesis/efectos de los fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Transcriptoma/efectos de los fármacos , Nanopartículas/química , Clorofila/metabolismoRESUMEN
Previous studies have reported the uptake of cerium oxide nanoparticles (nCeO2) by plants, but their physiological impacts are not yet well understood. This research was aimed to study the impact of nCeO2 on the oxidative stress and antioxidant defense system in germinating rice seeds. The seeds were germinated for 10 days in nCeO2 suspension at 62.5, 125, 250, and 500 mg L(-1) concentrations. The Ce uptake, growth performance, stress levels, membrane damage, and antioxidant responses in seedlings were analyzed. Ce in tissues increased with increased nCeO2 concentrations, but the seedlings showed no visible signs of toxicity. Biochemical assays and in vivo imaging of H2O2 revealed that, relative to the control, the 62.5 and 125 mg nCeO2 L(-1) treatments significantly reduced the H2O2 generation in both shoots and roots. Enhanced electrolyte leakage and lipid peroxidation were found in the shoots of seedlings grown at 500 mg nCeO2 L(-1). Altered enzyme activities and levels of ascorbate and free thiols resulting in enhanced membrane damage and photosynthetic stress in the shoots were observed at 500 mg nCeO2 L(-1). These findings demonstrate a nCeO2 concentration-dependent modification of oxidative stress and antioxidant defense system in rice seedlings.
Asunto(s)
Antioxidantes/metabolismo , Cerio/farmacología , Nanopartículas , Oryza/efectos de los fármacos , Oryza/metabolismo , Ácido Ascórbico/metabolismo , Cerio/farmacocinética , Clorofila/metabolismo , Electrólitos/metabolismo , Fluorescencia , Germinación/efectos de los fármacos , Peróxido de Hidrógeno/análisis , Peróxido de Hidrógeno/metabolismo , Procesamiento de Imagen Asistido por Computador/métodos , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/metabolismo , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrolloRESUMEN
Cerium oxide nanoparticles (nCeO2) have been shown to have significant interactions in plants; however, there are limited reports on their impacts in rice (Oryza sativa). Given the widespread environmental dispersal of nCeO2, it is paramount to understand its biochemical and molecular impacts on a globally important agricultural crop, such as rice. This study was carried out to determine the impact of nCeO2 on the oxidative stress, membrane damage, antioxidant enzymes' activities, and macromolecular changes in the roots of rice seedlings. Rice seeds (medium amylose) were grown for 10 days in nCeO2 suspensions (0-500 mg L(-1)). Results showed that Ce in root seedlings increased as the external nCeO2 increased without visible signs of toxicity. Relative to the control, the 62.5 mg nCeO2 L(-1) reduced the H2O2 generation in the roots by 75%. At 125 mg nCeO2 L(-1), the roots showed enhanced lipid peroxidation and electrolyte leakage, while at 500 mg L(-1), the nCeO2 increased the H2O2 generation in roots and reduced the fatty acid content. The lignin content decreased by 20% at 500 mg nCeO2 L(-1), despite the parallel increase in H2O2 content and peroxidase activities. Synchrotron µ-XRF confirmed the presence of Ce in the vascular tissues of the roots.
Asunto(s)
Cerio/química , Sustancias Macromoleculares/metabolismo , Nanopartículas/química , Oryza/enzimología , Estrés Oxidativo , Plantones/enzimología , Estrés Fisiológico , Amilosa/metabolismo , Antioxidantes/metabolismo , Cerio/metabolismo , Electrólitos/metabolismo , Ácidos Grasos/metabolismo , Peróxido de Hidrógeno/análisis , Peróxido de Hidrógeno/metabolismo , Lignina/metabolismo , Peroxidación de Lípido , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Oxidación-Reducción , Raíces de Plantas/enzimología , Plantones/metabolismo , Espectrometría por Rayos X , Sincrotrones , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismoRESUMEN
Introduction: The increasing use of cerium nanoparticles (CeO2-NPs) has made their influx in agroecosystems imminent through air and soil deposition or untreated wastewater irrigation. Another major pollutant associated with anthropogenic activities is Cd, which has adverse effects on plants, animals, and humans. The major source of the influx of Cd and Ce metals in the human food chain is contaminated food, making it an alarming issue; thus, there is a need to understand the factors that can reduce the potential damage of these heavy metals. Methods: The present investigation was conducted to evaluate the effect of CeO2-10-nm-NPs and Cd (alone and in combination) on Zea mays growth. A pot experiment (in sand) was conducted to check the effect of 0, 200, 400, 600, 1,000, and 2,000 mg of CeO2-10 nm-NPs/kg-1 dry sand alone and in combination with 0 and 0.5 mg Cd/kg-1 dry sand on maize seedlings grown in a partially controlled greenhouse environment, making a total of 12 treatments applied in four replicates under a factorial design. Maize seedling biomass, shoot and root growth, nutrient content, and root anatomy were measured. Results and discussion: The NPs were toxic to plant biomass (shoot and root dry weight), and growth at 2,000 ppm was the most toxic in Cd-0 sets. For Cd-0.5 sets, NPs applied at 1,000 ppm somewhat reverted Cd toxicity compared with the contaminated control (CC). Additionally, CeO2-NPs affected Cd translocation, and variable Ce uptake was observed in the presence of Cd compared with non-Cd applied sets. Furthermore, CeO2-NPs partially controlled the elemental content of roots and shoots (micronutrients such as B, Mn, Ni, Cu, Zn, Mo, and Fe and the elements Co and Si) and affected root anatomy.
RESUMEN
Cerium (Ce4+) and cerium oxide nanoparticles (CeO2-NPs) have diversified reported effects on plants. Once dispersed in the environment their fate is not well understood, especially in co-existence with other pollutants like cadmium (Cd). The effect of co-application of Ce and Cd are reported in various studies, but the role of Ce source (ionic or bulk) and nanoparticle size is still unknown in cereal plants like maize (Zea mays). To better understand the synergistic effects of Ce and Cd, 500 mg kg-1 Ce coming from ionic (Ce4+ as CeSO4) and CeO2 nano sources (10 nm, 50 nm, and 100 nm) alone and in combination with 0.5 mg Cd kg-1 sand were applied to maize seedlings. Growth, physiology, root structure, anatomy, and ionic homeostasis in maize were measured. The results revealed that Ce4+ resulted in overall decrease in seedling growth, biomass and resulted in higher heavy metal (in control sets) and Cd (in Cd spiked sets) uptake in maize seedlings' root and shoot. The effects of CeO2-NPs were found to be dependent on particle size; in fact, under Cd-0 (non-Cd spiked sets) CeO2-100 nm showed beneficial effects compared to the control. While under co-application with Cd, CeO2-50 nm showed net beneficial effects on maize seedling growth parameters. The Ce alone, and in combination with Cd, altered the root suberin barrier formation. Both ionic and nano Ce sources alone and in co-existence with Cd behaved differently for tissue elemental concentrations (Ce, Cd, micronutrients like B, Mn, Ni, Cu, Zn, Mo, Fe and elements Co, Si) suggesting a strong influence of Cd-Ce coexistence on the element's uptake and translocation in maize.
Asunto(s)
Cerio , Nanopartículas , Plantones , Cadmio/toxicidad , Zea mays , Raíces de Plantas , Nanopartículas/toxicidad , Nanopartículas/química , Cerio/químicaRESUMEN
This study investigated changes in metabolite compositions over three generation exposure of wheat (Triticum aestivum) to cerium oxide nanoparticles (CeO2-NPs) in low or high nitrogen soil. The goal was to determine if CeO2-NPs affects grains/seeds quality across generational exposure. Seeds from plants exposed for two generations to 0 or 500 mg CeO2-NPs per kg soil treatment were cultivated for third year in low or high nitrogen soil amended with 0 or 500 mg CeO2-NPs per kg soil. Metabolomics identified 180 metabolites. Multivariate analysis showed that continuous generational exposure to CeO2-NPs altered 18 and 11 metabolites in low N and high N grains, respectively. Interestingly, DNA/RNA metabolites such as thymidine, uracil, guanosine, deoxyguanosine, adenosine monophosphate were affected; a finding that has not been observed on DNA/RNA metabolites of plants exposed to nanoparticles. Nicotianamine, a metabolite playing crucial role in Fe storage in grains, decreased by 33% in grains continuously exposed for three generations to CeO2-NPs at high N soil. Notably, these grains also exhibited a concomitant decrease of 13-16% in Fe concentration. Together these changes suggest alterations in grain quality or implications in ecosystem processes (i.e., productivity, nutrient cycling, ecosystem stability) of progeny plants generationally-exposed to CeO2-NPs.
Asunto(s)
Nanopartículas del Metal , Cerio , Ecosistema , Metabolómica , TriticumRESUMEN
This study investigated the effects of third generation exposure to cerium oxide nanoparticles (CeO2-NPs) on biomass, elemental and 15N uptake, and fatty acid contents of wheat (Triticum aestivum). At low or high nitrogen treatment (48 or 112â¯mgâ¯N), seeds exposed for two generations to 0 or 500â¯mg CeO2-NPs per kg soil treatment were cultivated for third year in soil amended with 0 or 500â¯mg CeO2-NPs per kg soil. The results showed that parental and current exposures to CeO2-NPs increased the root biomass in daughter plants with greater magnitude of increase at low N than high N. When wheat received CeO2-NPs in year 3, root elemental contents increased primarily at low N, suggesting an important role of soil N availability in altering root nutrient acquisition. The δ15N ratios, previously shown to be altered by CeO2-NPs, were only affected by current and not parental exposure, indicating effects on N uptake and/or metabolism are not transferred from one generation to the next. Seed fatty acid composition was also influenced both by prior and current exposure to CeO2-NPs. The results suggest that risk assessments of NP exposure may need to include longer-term, transgenerational effects on growth and grain quality of agronomic crops.
Asunto(s)
Cerio/farmacología , Nanopartículas/química , Nitrógeno/metabolismo , Suelo/química , Triticum/efectos de los fármacos , Triticum/crecimiento & desarrollo , Biomasa , Cerio/química , Grano Comestible/efectos de los fármacos , Grano Comestible/crecimiento & desarrollo , Grano Comestible/metabolismo , Ácidos Grasos/metabolismo , Modelos Teóricos , Nitrógeno/análisis , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Triticum/metabolismoRESUMEN
The transformation of cerium oxide nanoparticles (CeO2-NPs) in soil and its role in plant uptake is a critical knowledge gap in the literature. This study investigated the reduction and speciation of CeO2-NPs in barley (Hordeum vulgare L.) cultivated in soil amended with 250 mg CeO2-NPs kg-1 soil. Synchrotron micro-X-ray fluorescence (µXRF) was employed for spatial localization and speciation of CeO2-NPs in thin sections of intact roots at the soil-root interface. Results revealed that Ce was largely localized in soil and at the root surface in nanoparticulate form (84-89%). However, a few hot spots on root surfaces revealed highly significant reduction (55-98%) of CeO2-NPs [Ce(IV)] to Ce(III) species. Interestingly, only roots in close proximity to hot spots showed Ce uptake which was largely CeO2 (89-91%) with very little amount Ce(III) (9-10%). These results suggest that the reduction of CeO2-NPs to Ce(III) is needed to facilitate uptake of Ce.
RESUMEN
The effects of cerium oxide nanoparticles (CeO2-NPs) on 15N/14N ratio (δ15N) in wheat and barley were investigated. Seedlings were exposed to 0 and 500 mg CeO2-NPs/L (Ce-0 and Ce-500, respectively) in hydroponic suspension supplied with NH4NO3, NH4 +, or NO3 -. N uptake and δ15N discrimination (i.e. differences in δ15N of plant and δ15N of N source) were measured. Results showed that N content and 15N abundance decreased in wheat but increased in barley. Ce-500 only induced whole-plant δ15N discrimination (-1.48, P ≤ 0.10) with a simultaneous decrease (P ≤ 0.05) in whole-plant δ15N (-3.24) compared to Ce-0 (-2.74) in wheat in NH4 +. Ce-500 decreased (P ≤ 0.01) root δ15N of wheat in NH4NO3 and NH4 + (3.23 and -2.25, respectively) compared to Ce-0 (4.96 and -1.27, respectively), but increased (P ≤ 0.05) root δ15N of wheat in NO3 - (3.27) compared to Ce-0 (2.60). Synchrotron micro-XRF revealed the presence of CeO2-NPs in shoots of wheat and barley regardless of N source. Although the longer-term consequences of CeO2-NP exposure on N uptake and metabolism are unknown, the results clearly show the potential for ENMs to interfere with plant metabolism of critical plant nutrients such as N even when toxicity is not observed.
RESUMEN
The intergenerational impact of engineered nanomaterials in plants is a key knowledge gap in the literature. A soil microcosm study was performed to assess the effects of multi-generational exposure of wheat (Triticum aestivum L.) to cerium oxide nanoparticles (CeO2-NPs). Seeds from plants that were exposed to 0, 125, and 500 mg CeO2-NPs/kg soil (Ce-0, Ce-125 or Ce-500, respectively) in first generation (S1) were cultivated in factorial combinations of Ce-0, Ce-125 or Ce-500 to produce second generation (S2) plants. The factorial combinations for first/second generation treatments in Ce-125 were S1-Ce-0/S2-Ce-0, S1-Ce-0/S2-Ce-125, S1-Ce-125/S2-Ce-0 and S1-Ce-125/S2-Ce-125, and in Ce-500 were S1-Ce-0/S2-Ce-0, S1-Ce-0/S2-Ce-500, S1-Ce-500/S2-Ce-0 and S1-Ce-500/S2-Ce-500. Agronomic, elemental, isotopic, and synchrotron X-ray fluorescence (XRF) and X-ray absorption near-edge spectroscopy (XANES) data were collected on second generation plants. Results showed that plants treated during the first generation only with either Ce-125 or Ce-500 (e.g. S1-Ce-125/S2-Ce-0 or S1-Ce-500/S2-Ce-0) had reduced accumulation of Ce (61 or 50%), Fe (49 or 58%) and Mn (34 or 41%) in roots, and δ15N (11 or 8%) in grains compared to the plants not treated in both generations (i.e. S1-Ce-0/S2-Ce-0). Plants treated in both generations with Ce-125 (i.e. S1-Ce-125/S2-Ce-125) produced grains that had lower Mn, Ca, K, Mg and P relative to plants treated in the second generation only (i.e. S1-Ce-0/S2-Ce-125). In addition, synchrotron XRF elemental chemistry maps of soil/plant thin-sections revealed limited transformation of CeO2-NPs with no evidence of plant uptake or accumulation. The findings demonstrated that first generation exposure of wheat to CeO2-NPs affects the physiology and nutrient profile of the second generation plants. However, the lack of concentration-dependent responses indicate that complex physiological processes are involved which alter uptake and metabolism of CeO2-NPs in wheat.
RESUMEN
There is lack of information about the effects of foliar applied nanoparticles on fruit quality. In this study, three week-old soil grown cucumber seedlings were foliar-exposed to nCeO2, nCuO, and corresponding bulk counterparts at 50, 100, and 200mg/L. Respective suspensions/solutions were sprayed to experimental units in a volume of 250ml. Net photosynthesis rate (Pn), stomatal conductance (Gs), and transpiration rate (E) were measured 15days after treatment application and in 74day-old plants. Yield, fruit characteristics (size, weight, and firmness), Ce, Cu, and nutritional elements were also measured. Results showed a nano-specific decrement on Pn (22% and 30%) and E (11% and 17%) in seedling leaves exposed to nCeO2 and nCuO at 200mg/L, respectively, compared with control. nCeO2 at 50mg/L, bCeO2 at 200mg/L, and all Cu treatments, except nCuO at 100mg/L, significantly reduced fruit firmness (p≤0.05), compared with control. However, nCuO at 200mg/L and bCuO at 50mg/L significantly increased fruit fresh weight (p≤0.05). At 200mg/L, nCeO2 and bCeO2 reduced fruit Zn by 25%, while nCuO and bCuO reduced fruit Mo by 51% and 44%, respectively, compared with control. This study has shown that when the route of exposure is the foliage, differences in particle size are less significant, compared to root-based exposure. To the authors' knowledge, this is the first report on the effect of foliar application of nCeO2 and nCuO upon yield and nutritional quality of cucumber.
Asunto(s)
Cucumis sativus/efectos de los fármacos , Contaminantes Ambientales/efectos adversos , Frutas/fisiología , Nanopartículas del Metal/efectos adversos , Valor Nutritivo/efectos de los fármacos , Cerio/efectos adversos , Cobre/efectos adversos , Cucumis sativus/fisiología , Relación Dosis-Respuesta a Droga , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/fisiologíaRESUMEN
Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO2, CA+nCeO2) bulk cerium oxide (bCeO2), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500mg/kg, both the uncoated and CA+nCeO2 increased shoot length by ~9 and ~13%, respectively, while bCeO2 and CeAc decreased shoot length by ~48 and ~26%, respectively, compared with MPW (p≤0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA+nCeO2 at 250mg/kg, but reduced by bCeO2 at 62.5mg/kg, compared with MPW. At 250 and 500mg/kg, nCeO2 increased Ce in roots by 10 and 7 times, compared to CA+nCeO2, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO2 nor CA+nCeO2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO2 at 62.5mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO2 on tomato plants.
Asunto(s)
Acetatos/metabolismo , Cerio/metabolismo , Ácido Cítrico/metabolismo , Materiales Biocompatibles Revestidos/metabolismo , Nanopartículas del Metal , Solanum lycopersicum/efectos de los fármacos , Clorofila/metabolismo , Frutas/efectos de los fármacos , Frutas/enzimología , Frutas/crecimiento & desarrollo , Frutas/fisiología , Solanum lycopersicum/enzimología , Solanum lycopersicum/crecimiento & desarrollo , Solanum lycopersicum/fisiología , Proteínas de Plantas/metabolismoRESUMEN
Cerium oxide nanoparticles (nCeO2) have extensive industrial applications, and concerns regarding their threat to the environment have been raised. This study includes structural analysis of intact root xylem of rice (Oryza sativaL.), wheat (Triticum aestivumL.), and barley (Hordeum vulgareL.) seedlings exposed to nCeO2 suspensions (0, 62.5, 125, 250, and 500 mg L(-1)). Fourier transform infrared microspectroscopy was applied to determine compositional alterations in the root xylem, and principal component analysis (PCA) was carried out to examine spectral differences between nCeO2 treatments. Results demonstrated that nCeO2 at ≥ 125 mg L(-1) changed the region of spectra around 1696-1760 cm(-1) in rice root, 125 and 250 mg L(-1) modified 1744-1792 cm(-1) in wheat, and 62.5 and 125 mg L(-1) altered 1727-1760 cm(-1) in barley. PCA afforded the clustering of nCeO2 treatments at 0 and 62.5 mg L(-1) in rice and wheat and 0 and 500 mg L(-1) in barley. Furthermore, major peaks at 1744 or 1760 cm(-1) appeared in primary PC and 1728 cm(-1) in secondary PC score loadings. These findings illustrated that nCeO2 induced compositional modifications in the root xylem of cereals.
Asunto(s)
Cerio/farmacología , Hordeum/efectos de los fármacos , Oryza/efectos de los fármacos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Triticum/efectos de los fármacos , Hordeum/química , Nanopartículas , Oryza/química , Raíces de Plantas/efectos de los fármacos , Análisis de Componente Principal , Plantones/química , Plantones/efectos de los fármacos , Triticum/químicaRESUMEN
The increased production and use of nanoparticles (NPs) has generated concerns about their impact on living organisms. In this study, nCu, bulk Cu, nCuO, bulk CuO, Cu(OH)2 (CuPRO 2005, Kocide 3000), and CuCl2 were exposed for 15 days to 10 days-old hydroponically grown lettuce (Lactuca sativa) and alfalfa (Medicago sativa). Each compound was applied at 0, 5, 10, and 20 mg L(-1). At harvest, we measured the size of the plants and determined the concentration of Cu, macro and microelements by using ICP-OES. Catalase and ascorbate peroxidase activity was also determined. Results showed that all Cu NPs/compounds reduced the root length by 49% in both plant species. All Cu NPs/compounds increased Cu, P, and S (>100%, >50%, and >20%, respectively) in alfalfa shoots and decreased P and Fe in lettuce shoot (>50% and >50%, respectively, excluding Fe in CuCl2 treatment). Biochemical assays showed reduced catalase activity in alfalfa (root and shoot) and increased ascorbate peroxidase activity in roots of both plant species. Results suggest that Cu NPs/compounds not only reduced the size of the plants but altered nutrient content and enzyme activity in both plant species.
Asunto(s)
Cobre/toxicidad , Lactuca/efectos de los fármacos , Medicago sativa/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Contaminantes Químicos del Agua/toxicidad , Catalasa , Hidroponía , Lactuca/metabolismoRESUMEN
ZnO nanoparticles (NPs) are reported as potentially phytotoxic in hydroponic and soil media. However, studies on ZnO NPs toxicity in a plant inoculated with bacterium in soil are limited. In this study, ZnO NPs, bulk ZnO, and ZnCl2 were exposed to the symbiotic alfalfa (Medicago sativa L.)-Sinorhizobium meliloti association at concentrations ranging from 0 to 750 mg/kg soil. Plant growth, Zn bioaccumulation, dry biomass, leaf area, total protein, and catalase (CAT) activity were measured in 30 day-old plants. Results showed 50% germination reduction by bulk ZnO at 500 and 750 mg/kg and all ZnCl2 concentrations. ZnO NPs and ionic Zn reduced root and shoot biomass by 80% and 25%, respectively. Conversely, bulk ZnO at 750 mg/kg increased shoot and root biomass by 225% and 10%, respectively, compared to control. At 500 and 750 mg/kg, ZnCl2 reduced CAT activity in stems and leaves. Total leaf protein significantly decreased as external ZnCl2 concentration increased. STEM-EDX imaging revealed the presence of ZnO particles in the root, stem, leaf, and nodule tissues. ZnO NPs showed less toxicity compared to ZnCl2 and bulk ZnO found to be growth enhancing on measured traits. These findings are significant to reveal the toxicity effects of different Zn species (NPs, bulk, and ionic Zn) into environmentally important plant-bacterial system in soil.
Asunto(s)
Medicago sativa/efectos de los fármacos , Nanopartículas/toxicidad , Sinorhizobium meliloti/efectos de los fármacos , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Óxido de Zinc/toxicidad , Hidroponía , Medicago sativa/microbiología , Medicago sativa/fisiología , Sinorhizobium meliloti/fisiología , Suelo , SimbiosisRESUMEN
A soil microcosm study was performed to examine the impacts of cerium oxide nanoparticles (nCeO2) on the physiology, productivity, and macromolecular composition of barley (Hordeum vulgare L.). The plants were cultivated in soil treated with nCeO2 at 0, 125, 250, and 500 mg kg(-1) (control, nCeO2-L, nCeO2-M, and nCeO2-H, respectively). Accumulation of Ce in leaves/grains and its effects on plant stress and nutrient loading were analyzed. The data revealed that nCeO2-H promoted plant development resulting in 331 % increase in shoot biomass compared with the control. nCeO2 treatment modified the stress levels in leaves without apparent signs of toxicity. However, plants exposed to nCeO2-H treatment did not form grains. Compared with control, nCeO2-M enhanced grain Ce accumulation by as much as 294 % which was accompanied by remarkable increases in P, K, Ca, Mg, S, Fe, Zn, Cu, and Al. Likewise, nCeO2-M enhanced the methionine, aspartic acid, threonine, tyrosine, arginine, and linolenic acid contents in the grains by up to 617, 31, 58, 141, 378, and 2.47 % respectively, compared with the rest of the treatments. The findings illustrate the beneficial and harmful effects of nanoceria in barley.
Asunto(s)
Cerio/farmacología , Cerio/toxicidad , Hordeum/efectos de los fármacos , Nanopartículas/toxicidad , Contaminantes del Suelo/farmacología , Contaminantes del Suelo/toxicidad , Biomasa , Grano Comestible/efectos de los fármacos , Grano Comestible/crecimiento & desarrollo , Hordeum/crecimiento & desarrollo , Hordeum/metabolismo , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/metabolismoRESUMEN
The implications of engineered nanomaterials on crop productivity and food quality are not yet well understood. The impact of cerium oxide nanoparticles (nCeO2) on growth and yield attributes and nutritional composition in wheat (Triticum aestivum L.) was examined. Wheat was cultivated to grain production in soil amended with 0, 125, 250, and 500 mg of nCeO2/kg (control, nCeO2-L, nCeO2-M, and nCeO2-H, respectively). At harvest, grains and tissues were analyzed for mineral, fatty acid, and amino acid content. Results showed that, relative to the control, nCeO2-H improved plant growth, shoot biomass, and grain yield by 9.0%, 12.7%, and 36.6%, respectively. Ce accumulation in roots increased at increased nCeO2 concentration but did not change across treatments in leaves, hull, and grains, indicating a lack of Ce transport to the above-ground tissues. nCeO2 modified S and Mn storage in grains. nCeO2-L modified the amino acid composition and increased linolenic acid by up to 6.17% but decreased linoleic acid by up to 1.63%, compared to the other treatments. The findings suggest the potential of nanoceria to modify crop physiology and food quality with unknown consequences for living organisms.